text: import errno
  import functools
  import inspect
  import json
  import logging
  import os
  import select
  import shlex
  import shutil
  import struct
  import sys
  import tempfile
  import textwrap
  import time
  import traceback
  from subprocess import Popen, PIPE
  
  from . import __version__
  from .compress import LZ4
  from .constants import *  # NOQA
  from .helpers import Error, IntegrityError
  from .helpers import bin_to_hex
  from .helpers import get_base_dir
  from .helpers import get_limited_unpacker
  from .helpers import replace_placeholders
  from .helpers import sysinfo
  from .helpers import format_file_size
  from .helpers import truncate_and_unlink
  from .helpers import prepare_subprocess_env
  from .logger import create_logger, setup_logging
  from .helpers import msgpack
  from .repository import Repository
  from .version import parse_version, format_version
  from .algorithms.checksums import xxh64
  
  logger = create_logger(__name__)
  
  RPC_PROTOCOL_VERSION = 2
  BORG_VERSION = parse_version(__version__)
  MSGID, MSG, ARGS, RESULT = b'i', b'm', b'a', b'r'
  
  MAX_INFLIGHT = 100
  
  RATELIMIT_PERIOD = 0.1
  
  
  def os_write(fd, data):
      """os.write wrapper so we do not lose data for partial writes."""
      # TODO: this issue is fixed in cygwin since at least 2.8.0, remove this
      #       wrapper / workaround when this version is considered ancient.
      # This is happening frequently on cygwin due to its small pipe buffer size of only 64kiB
      # and also due to its different blocking pipe behaviour compared to Linux/*BSD.
      # Neither Linux nor *BSD ever do partial writes on blocking pipes, unless interrupted by a
      # signal, in which case serve() would terminate.
      amount = remaining = len(data)
      while remaining:
          count = os.write(fd, data)
          remaining -= count
          if not remaining:
              break
          data = data[count:]
          time.sleep(count * 1e-09)
      return amount
  
  
  class ConnectionClosed(Error):
      """Connection closed by remote host"""
  
  
  class ConnectionClosedWithHint(ConnectionClosed):
      """Connection closed by remote host. {}"""
  
  
  class PathNotAllowed(Error):
      """Repository path not allowed: {}"""
  
  
  class InvalidRPCMethod(Error):
      """RPC method {} is not valid"""
  
  
  class UnexpectedRPCDataFormatFromClient(Error):
      """Borg {}: Got unexpected RPC data format from client."""
  
  
  class UnexpectedRPCDataFormatFromServer(Error):
      """Got unexpected RPC data format from server:\n{}"""
  
      def __init__(self, data):
          try:
              data = data.decode()[:128]
          except UnicodeDecodeError:
              data = data[:128]
              data = ['%02X' % byte for byte in data]
              data = textwrap.fill(' '.join(data), 16 * 3)
          super().__init__(data)
  
  
  # Protocol compatibility:
  # In general the server is responsible for rejecting too old clients and the client it responsible for rejecting
  # too old servers. This ensures that the knowledge what is compatible is always held by the newer component.
  #
  # The server can do checks for the client version in RepositoryServer.negotiate. If the client_data is 2 then
  # client is in the version range [0.29.0, 1.0.x] inclusive. For newer clients client_data is a dict which contains
  # client_version.
  #
  # For the client the return of the negotiate method is either 2 if the server is in the version range [0.29.0, 1.0.x]
  # inclusive, or it is a dict which includes the server version.
  #
  # All method calls on the remote repository object must be whitelisted in RepositoryServer.rpc_methods and have api
  # stubs in RemoteRepository. The @api decorator on these stubs is used to set server version requirements.
  #
  # Method parameters are identified only by name and never by position. Unknown parameters are ignored by the server side.
  # If a new parameter is important and may not be ignored, on the client a parameter specific version requirement needs
  # to be added.
  # When parameters are removed, they need to be preserved as defaulted parameters on the client stubs so that older
  # servers still get compatible input.
  
  
  compatMap = {
      'check': ('repair', 'save_space', ),
      'commit': ('save_space', ),
      'rollback': (),
      'destroy': (),
      '__len__': (),
      'list': ('limit', 'marker', ),
      'put': ('id', 'data', ),
      'get': ('id', ),
      'delete': ('id', ),
      'save_key': ('keydata', ),
      'load_key': (),
      'break_lock': (),
      'negotiate': ('client_data', ),
      'open': ('path', 'create', 'lock_wait', 'lock', 'exclusive', 'append_only', ),
      'get_free_nonce': (),
      'commit_nonce_reservation': ('next_unreserved', 'start_nonce', ),
  }
  
  
  def decode_keys(d):
      return {k.decode(): d[k] for k in d}
  
  
  class RepositoryServer:  # pragma: no cover
      rpc_methods = (
          '__len__',
          'check',
          'commit',
          'delete',
          'destroy',
          'get',
          'list',
          'scan',
          'negotiate',
          'open',
          'put',
          'rollback',
          'save_key',
          'load_key',
          'break_lock',
          'get_free_nonce',
          'commit_nonce_reservation',
          'inject_exception',
      )
  
      def __init__(self, restrict_to_paths, restrict_to_repositories, append_only, storage_quota):
          self.repository = None
          self.restrict_to_paths = restrict_to_paths
          self.restrict_to_repositories = restrict_to_repositories
          # This flag is parsed from the serve command line via Archiver.do_serve,
          # i.e. it reflects local system policy and generally ranks higher than
          # whatever the client wants, except when initializing a new repository
          # (see RepositoryServer.open below).
          self.append_only = append_only
          self.storage_quota = storage_quota
          self.client_version = parse_version('1.0.8')  # fallback version if client is too old to send version information
  
      def positional_to_named(self, method, argv):
          """Translate from positional protocol to named protocol."""
          try:
              return {name: argv[pos] for pos, name in enumerate(compatMap[method])}
          except IndexError:
              if method == 'open' and len(argv) == 4:
                  # borg clients < 1.0.7 use open() with 4 args
                  mapping = compatMap[method][:4]
              else:
                  raise
              return {name: argv[pos] for pos, name in enumerate(mapping)}
  
      def filter_args(self, f, kwargs):
          """Remove unknown named parameters from call, because client did (implicitly) say it's ok."""
          known = set(inspect.signature(f).parameters)
          return {name: kwargs[name] for name in kwargs if name in known}
  
      def serve(self):
          stdin_fd = sys.stdin.fileno()
          stdout_fd = sys.stdout.fileno()
          stderr_fd = sys.stdout.fileno()
          os.set_blocking(stdin_fd, False)
          os.set_blocking(stdout_fd, True)
          os.set_blocking(stderr_fd, True)
          unpacker = get_limited_unpacker('server')
          while True:
              r, w, es = select.select([stdin_fd], [], [], 10)
              if r:
                  data = os.read(stdin_fd, BUFSIZE)
                  if not data:
                      if self.repository is not None:
                          self.repository.close()
                      else:
                          os_write(stderr_fd, 'Borg {}: Got connection close before repository was opened.\n'
                                   .format(__version__).encode())
                      return
                  unpacker.feed(data)
                  for unpacked in unpacker:
                      if isinstance(unpacked, dict):
                          dictFormat = True
                          msgid = unpacked[MSGID]
                          method = unpacked[MSG].decode()
                          args = decode_keys(unpacked[ARGS])
                      elif isinstance(unpacked, tuple) and len(unpacked) == 4:
                          dictFormat = False
                          # The first field 'type' was always 1 and has always been ignored
                          _, msgid, method, args = unpacked
                          method = method.decode()
                          args = self.positional_to_named(method, args)
                      else:
                          if self.repository is not None:
                              self.repository.close()
                          raise UnexpectedRPCDataFormatFromClient(__version__)
                      try:
                          if method not in self.rpc_methods:
                              raise InvalidRPCMethod(method)
                          try:
                              f = getattr(self, method)
                          except AttributeError:
                              f = getattr(self.repository, method)
                          args = self.filter_args(f, args)
                          res = f(**args)
                      except BaseException as e:
                          if dictFormat:
                              ex_short = traceback.format_exception_only(e.__class__, e)
                              ex_full = traceback.format_exception(*sys.exc_info())
                              ex_trace = True
                              if isinstance(e, Error):
                                  ex_short = [e.get_message()]
                                  ex_trace = e.traceback
                              if isinstance(e, (Repository.DoesNotExist, Repository.AlreadyExists, PathNotAllowed)):
                                  # These exceptions are reconstructed on the client end in RemoteRepository.call_many(),
                                  # and will be handled just like locally raised exceptions. Suppress the remote traceback
                                  # for these, except ErrorWithTraceback, which should always display a traceback.
                                  pass
                              else:
                                  logging.debug('\n'.join(ex_full))
  
                              try:
                                  msg = msgpack.packb({MSGID: msgid,
                                                      b'exception_class': e.__class__.__name__,
                                                      b'exception_args': e.args,
                                                      b'exception_full': ex_full,
                                                      b'exception_short': ex_short,
                                                      b'exception_trace': ex_trace,
                                                      b'sysinfo': sysinfo()})
                              except TypeError:
                                  msg = msgpack.packb({MSGID: msgid,
                                                      b'exception_class': e.__class__.__name__,
                                                      b'exception_args': [x if isinstance(x, (str, bytes, int)) else None
                                                                          for x in e.args],
                                                      b'exception_full': ex_full,
                                                      b'exception_short': ex_short,
                                                      b'exception_trace': ex_trace,
                                                      b'sysinfo': sysinfo()})
  
                              os_write(stdout_fd, msg)
                          else:
                              if isinstance(e, (Repository.DoesNotExist, Repository.AlreadyExists, PathNotAllowed)):
                                  # These exceptions are reconstructed on the client end in RemoteRepository.call_many(),
                                  # and will be handled just like locally raised exceptions. Suppress the remote traceback
                                  # for these, except ErrorWithTraceback, which should always display a traceback.
                                  pass
                              else:
                                  if isinstance(e, Error):
                                      tb_log_level = logging.ERROR if e.traceback else logging.DEBUG
                                      msg = e.get_message()
                                  else:
                                      tb_log_level = logging.ERROR
                                      msg = '%s Exception in RPC call' % e.__class__.__name__
                                  tb = '%s\n%s' % (traceback.format_exc(), sysinfo())
                                  logging.error(msg)
                                  logging.log(tb_log_level, tb)
                              exc = 'Remote Exception (see remote log for the traceback)'
                              os_write(stdout_fd, msgpack.packb((1, msgid, e.__class__.__name__, exc)))
                      else:
                          if dictFormat:
                              os_write(stdout_fd, msgpack.packb({MSGID: msgid, RESULT: res}))
                          else:
                              os_write(stdout_fd, msgpack.packb((1, msgid, None, res)))
              if es:
                  self.repository.close()
                  return
  
      def negotiate(self, client_data):
          # old format used in 1.0.x
          if client_data == RPC_PROTOCOL_VERSION:
              return RPC_PROTOCOL_VERSION
          # clients since 1.1.0b3 use a dict as client_data
          # clients since 1.1.0b6 support json log format from server
          if isinstance(client_data, dict):
              self.client_version = client_data[b'client_version']
              level = logging.getLevelName(logging.getLogger('').level)
              setup_logging(is_serve=True, json=True, level=level)
              logger.debug('Initialized logging system for JSON-based protocol')
          else:
              self.client_version = BORG_VERSION  # seems to be newer than current version (no known old format)
  
          # not a known old format, send newest negotiate this version knows
          return {'server_version': BORG_VERSION}
  
      def _resolve_path(self, path):
          if isinstance(path, bytes):
              path = os.fsdecode(path)
          # Leading slash is always present with URI (ssh://), but not with short-form (who@host:path).
          if path.startswith('/~/'):  # /~/x = path x relative to home dir
              path = os.path.join(get_base_dir(), path[3:])
          elif path.startswith('~/'):
              path = os.path.join(get_base_dir(), path[2:])
          elif path.startswith('/~'):  # /~username/x = relative to "user" home dir
              path = os.path.expanduser(path[1:])
          elif path.startswith('~'):
              path = os.path.expanduser(path)
          elif path.startswith('/./'):  # /./x = path x relative to cwd
              path = path[3:]
          return os.path.realpath(path)
  
      def open(self, path, create=False, lock_wait=None, lock=True, exclusive=None, append_only=False,
               make_parent_dirs=False):
          logging.debug('Resolving repository path %r', path)
          path = self._resolve_path(path)
          logging.debug('Resolved repository path to %r', path)
          path_with_sep = os.path.join(path, '')  # make sure there is a trailing slash (os.sep)
          if self.restrict_to_paths:
              # if --restrict-to-path P is given, we make sure that we only operate in/below path P.
              # for the prefix check, it is important that the compared paths both have trailing slashes,
              # so that a path /foobar will NOT be accepted with --restrict-to-path /foo option.
              for restrict_to_path in self.restrict_to_paths:
                  restrict_to_path_with_sep = os.path.join(os.path.realpath(restrict_to_path), '')  # trailing slash
                  if path_with_sep.startswith(restrict_to_path_with_sep):
                      break
              else:
                  raise PathNotAllowed(path)
          if self.restrict_to_repositories:
              for restrict_to_repository in self.restrict_to_repositories:
                  restrict_to_repository_with_sep = os.path.join(os.path.realpath(restrict_to_repository), '')
                  if restrict_to_repository_with_sep == path_with_sep:
                      break
              else:
                  raise PathNotAllowed(path)
          # "borg init" on "borg serve --append-only" (=self.append_only) does not create an append only repo,
          # while "borg init --append-only" (=append_only) does, regardless of the --append-only (self.append_only)
          # flag for serve.
          append_only = (not create and self.append_only) or append_only
          self.repository = Repository(path, create, lock_wait=lock_wait, lock=lock,
                                       append_only=append_only,
                                       storage_quota=self.storage_quota,
                                       exclusive=exclusive,
                                       make_parent_dirs=make_parent_dirs)
          self.repository.__enter__()  # clean exit handled by serve() method
          return self.repository.id
  
      def inject_exception(self, kind):
          kind = kind.decode()
          s1 = 'test string'
          s2 = 'test string2'
          if kind == 'DoesNotExist':
              raise Repository.DoesNotExist(s1)
          elif kind == 'AlreadyExists':
              raise Repository.AlreadyExists(s1)
          elif kind == 'CheckNeeded':
              raise Repository.CheckNeeded(s1)
          elif kind == 'IntegrityError':
              raise IntegrityError(s1)
          elif kind == 'PathNotAllowed':
              raise PathNotAllowed('foo')
          elif kind == 'ObjectNotFound':
              raise Repository.ObjectNotFound(s1, s2)
          elif kind == 'InvalidRPCMethod':
              raise InvalidRPCMethod(s1)
          elif kind == 'divide':
              0 // 0
  
  
  class SleepingBandwidthLimiter:
      def __init__(self, limit):
          if limit:
              self.ratelimit = int(limit * RATELIMIT_PERIOD)
              self.ratelimit_last = time.monotonic()
              self.ratelimit_quota = self.ratelimit
          else:
              self.ratelimit = None
  
      def write(self, fd, to_send):
          if self.ratelimit:
              now = time.monotonic()
              if self.ratelimit_last + RATELIMIT_PERIOD <= now:
                  self.ratelimit_quota += self.ratelimit
                  if self.ratelimit_quota > 2 * self.ratelimit:
                      self.ratelimit_quota = 2 * self.ratelimit
                  self.ratelimit_last = now
              if self.ratelimit_quota == 0:
                  tosleep = self.ratelimit_last + RATELIMIT_PERIOD - now
                  time.sleep(tosleep)
                  self.ratelimit_quota += self.ratelimit
                  self.ratelimit_last = time.monotonic()
              if len(to_send) > self.ratelimit_quota:
                  to_send = to_send[:self.ratelimit_quota]
          written = os.write(fd, to_send)
          if self.ratelimit:
              self.ratelimit_quota -= written
          return written
  
  
  def api(*, since, **kwargs_decorator):
      """Check version requirements and use self.call to do the remote method call.
  
      <since> specifies the version in which borg introduced this method,
      calling this method when connected to an older version will fail without transmiting
      anything to the server.
  
      Further kwargs can be used to encode version specific restrictions.
      If a previous hardcoded behaviour is parameterized in a version, this allows calls that
      use the previously hardcoded behaviour to pass through and generates an error if another
      behaviour is requested by the client.
  
      e.g. when 'append_only' was introduced in 1.0.7 the previous behaviour was what now is append_only=False.
      Thus @api(..., append_only={'since': parse_version('1.0.7'), 'previously': False}) allows calls
      with append_only=False for all version but rejects calls using append_only=True on versions older than 1.0.7.
      """
      def decorator(f):
          @functools.wraps(f)
          def do_rpc(self, *args, **kwargs):
              sig = inspect.signature(f)
              bound_args = sig.bind(self, *args, **kwargs)
              named = {}  # Arguments for the remote process
              extra = {}  # Arguments for the local process
              for name, param in sig.parameters.items():
                  if name == 'self':
                      continue
                  if name in bound_args.arguments:
                      if name == 'wait':
                          extra[name] = bound_args.arguments[name]
                      else:
                          named[name] = bound_args.arguments[name]
                  else:
                      if param.default is not param.empty:
                          named[name] = param.default
  
              if self.server_version < since:
                  raise self.RPCServerOutdated(f.__name__, format_version(since))
  
              for name, restriction in kwargs_decorator.items():
                  if restriction['since'] <= self.server_version:
                      continue
                  if 'previously' in restriction and named[name] == restriction['previously']:
                      continue
                  if restriction.get('dontcare', False):
                      continue
  
                  raise self.RPCServerOutdated("{0} {1}={2!s}".format(f.__name__, name, named[name]),
                                               format_version(restriction['since']))
  
              return self.call(f.__name__, named, **extra)
          return do_rpc
      return decorator
  
  
  class RemoteRepository:
      extra_test_args = []
  
      class RPCError(Exception):
          def __init__(self, unpacked):
              # for borg < 1.1: unpacked only has b'exception_class' as key
              # for borg 1.1+: unpacked has keys: b'exception_args', b'exception_full', b'exception_short', b'sysinfo'
              self.unpacked = unpacked
  
          def get_message(self):
              if b'exception_short' in self.unpacked:
                  return b'\n'.join(self.unpacked[b'exception_short']).decode()
              else:
                  return self.exception_class
  
          @property
          def traceback(self):
              return self.unpacked.get(b'exception_trace', True)
  
          @property
          def exception_class(self):
              return self.unpacked[b'exception_class'].decode()
  
          @property
          def exception_full(self):
              if b'exception_full' in self.unpacked:
                  return b'\n'.join(self.unpacked[b'exception_full']).decode()
              else:
                  return self.get_message() + '\nRemote Exception (see remote log for the traceback)'
  
          @property
          def sysinfo(self):
              if b'sysinfo' in self.unpacked:
                  return self.unpacked[b'sysinfo'].decode()
              else:
                  return ''
  
      class RPCServerOutdated(Error):
          """Borg server is too old for {}. Required version {}"""
  
          @property
          def method(self):
              return self.args[0]
  
          @property
          def required_version(self):
              return self.args[1]
  
      # If compatibility with 1.0.x is not longer needed, replace all checks of this with True and simplify the code
      dictFormat = False  # outside of __init__ for testing of legacy free protocol
  
      def __init__(self, location, create=False, exclusive=False, lock_wait=None, lock=True, append_only=False,
                   make_parent_dirs=False, args=None):
          self.location = self._location = location
          self.preload_ids = []
          self.msgid = 0
          self.rx_bytes = 0
          self.tx_bytes = 0
          self.to_send = b''
          self.stderr_received = b''  # incomplete stderr line bytes received (no \n yet)
          self.chunkid_to_msgids = {}
          self.ignore_responses = set()
          self.responses = {}
          self.async_responses = {}
          self.shutdown_time = None
          self.ratelimit = SleepingBandwidthLimiter(args.remote_ratelimit * 1024 if args and args.remote_ratelimit else 0)
          self.unpacker = get_limited_unpacker('client')
          self.server_version = parse_version('1.0.8')  # fallback version if server is too old to send version information
          self.p = None
          self._args = args
          testing = location.host == '__testsuite__'
          # when testing, we invoke and talk to a borg process directly (no ssh).
          # when not testing, we invoke the system-installed ssh binary to talk to a remote borg.
          env = prepare_subprocess_env(system=not testing)
          borg_cmd = self.borg_cmd(args, testing)
          if not testing:
              borg_cmd = self.ssh_cmd(location) + borg_cmd
          logger.debug('SSH command line: %s', borg_cmd)
          self.p = Popen(borg_cmd, bufsize=0, stdin=PIPE, stdout=PIPE, stderr=PIPE, env=env)
          self.stdin_fd = self.p.stdin.fileno()
          self.stdout_fd = self.p.stdout.fileno()
          self.stderr_fd = self.p.stderr.fileno()
          os.set_blocking(self.stdin_fd, False)
          os.set_blocking(self.stdout_fd, False)
          os.set_blocking(self.stderr_fd, False)
          self.r_fds = [self.stdout_fd, self.stderr_fd]
          self.x_fds = [self.stdin_fd, self.stdout_fd, self.stderr_fd]
  
          try:
              try:
                  version = self.call('negotiate', {'client_data': {
                      b'client_version': BORG_VERSION,
                  }})
              except ConnectionClosed:
                  raise ConnectionClosedWithHint('Is borg working on the server?') from None
              if version == RPC_PROTOCOL_VERSION:
                  self.dictFormat = False
              elif isinstance(version, dict) and b'server_version' in version:
                  self.dictFormat = True
                  self.server_version = version[b'server_version']
              else:
                  raise Exception('Server insisted on using unsupported protocol version %s' % version)
  
              def do_open():
                  self.id = self.open(path=self.location.path, create=create, lock_wait=lock_wait,
                                      lock=lock, exclusive=exclusive, append_only=append_only,
                                      make_parent_dirs=make_parent_dirs)
  
              if self.dictFormat:
                  do_open()
              else:
                  # Ugly detection of versions prior to 1.0.7: If open throws it has to be 1.0.6 or lower
                  try:
                      do_open()
                  except self.RPCError as err:
                      if err.exception_class != 'TypeError':
                          raise
                      msg = """\
  Please note:
  If you see a TypeError complaining about the number of positional arguments
  given to open(), you can ignore it if it comes from a borg version < 1.0.7.
  This TypeError is a cosmetic side effect of the compatibility code borg
  clients >= 1.0.7 have to support older borg servers.
  This problem will go away as soon as the server has been upgraded to 1.0.7+.
  """
                      # emit this msg in the same way as the 'Remote: ...' lines that show the remote TypeError
                      sys.stderr.write(msg)
                      self.server_version = parse_version('1.0.6')
                      compatMap['open'] = ('path', 'create', 'lock_wait', 'lock', )
                      # try again with corrected version and compatMap
                      do_open()
          except Exception:
              self.close()
              raise
  
      def __del__(self):
          if len(self.responses):
              logging.debug('still %d cached responses left in RemoteRepository' % (len(self.responses),))
          if self.p:
              self.close()
              assert False, 'cleanup happened in Repository.__del__'
  
      def __repr__(self):
          return '<%s %s>' % (self.__class__.__name__, self.location.canonical_path())
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_val, exc_tb):
          try:
              if exc_type is not None:
                  self.shutdown_time = time.monotonic() + 30
                  self.rollback()
          finally:
              # in any case, we want to cleanly close the repo, even if the
              # rollback can not succeed (e.g. because the connection was
              # already closed) and raised another exception:
              logger.debug('RemoteRepository: %s bytes sent, %s bytes received, %d messages sent',
                           format_file_size(self.tx_bytes), format_file_size(self.rx_bytes), self.msgid)
              self.close()
  
      @property
      def id_str(self):
          return bin_to_hex(self.id)
  
      def borg_cmd(self, args, testing):
          """return a borg serve command line"""
          # give some args/options to 'borg serve' process as they were given to us
          opts = []
          if args is not None:
              opts.append('--umask=%03o' % args.umask)
              root_logger = logging.getLogger()
              if root_logger.isEnabledFor(logging.DEBUG):
                  opts.append('--debug')
              elif root_logger.isEnabledFor(logging.INFO):
                  opts.append('--info')
              elif root_logger.isEnabledFor(logging.WARNING):
                  pass  # warning is default
              elif root_logger.isEnabledFor(logging.ERROR):
                  opts.append('--error')
              elif root_logger.isEnabledFor(logging.CRITICAL):
                  opts.append('--critical')
              else:
                  raise ValueError('log level missing, fix this code')
  
              # Tell the remote server about debug topics it may need to consider.
              # Note that debug topics are usable for "spew" or "trace" logs which would
              # be too plentiful to transfer for normal use, so the server doesn't send
              # them unless explicitly enabled.
              #
              # Needless to say, if you do --debug-topic=repository.compaction, for example,
              # with a 1.0.x server it won't work, because the server does not recognize the
              # option.
              #
              # This is not considered a problem, since this is a debugging feature that
              # should not be used for regular use.
              for topic in args.debug_topics:
                  if '.' not in topic:
                      topic = 'borg.debug.' + topic
                  if 'repository' in topic:
                      opts.append('--debug-topic=%s' % topic)
  
              if 'storage_quota' in args and args.storage_quota:
                  opts.append('--storage-quota=%s' % args.storage_quota)
          env_vars = []
          if testing:
              return env_vars + [sys.executable, '-m', 'borg.archiver', 'serve'] + opts + self.extra_test_args
          else:  # pragma: no cover
              remote_path = args.remote_path or os.environ.get('BORG_REMOTE_PATH', 'borg')
              remote_path = replace_placeholders(remote_path)
              return env_vars + [remote_path, 'serve'] + opts
  
      def ssh_cmd(self, location):
          """return a ssh command line that can be prefixed to a borg command line"""
          rsh = self._args.rsh or os.environ.get('BORG_RSH', 'ssh')
          args = shlex.split(rsh)
          if location.port:
              args += ['-p', str(location.port)]
          if location.user:
              args.append('%s@%s' % (location.user, location.host))
          else:
              args.append('%s' % location.host)
          return args
  
      def named_to_positional(self, method, kwargs):
          return [kwargs[name] for name in compatMap[method]]
  
      def call(self, cmd, args, **kw):
          for resp in self.call_many(cmd, [args], **kw):
              return resp
  
      def call_many(self, cmd, calls, wait=True, is_preloaded=False, async_wait=True):
          if not calls and cmd != 'async_responses':
              return
  
          def pop_preload_msgid(chunkid):
              msgid = self.chunkid_to_msgids[chunkid].pop(0)
              if not self.chunkid_to_msgids[chunkid]:
                  del self.chunkid_to_msgids[chunkid]
              return msgid
  
          def handle_error(unpacked):
              error = unpacked[b'exception_class'].decode()
              old_server = b'exception_args' not in unpacked
              args = unpacked.get(b'exception_args')
  
              if error == 'DoesNotExist':
                  raise Repository.DoesNotExist(self.location.orig)
              elif error == 'AlreadyExists':
                  raise Repository.AlreadyExists(self.location.orig)
              elif error == 'CheckNeeded':
                  raise Repository.CheckNeeded(self.location.orig)
              elif error == 'IntegrityError':
                  if old_server:
                      raise IntegrityError('(not available)')
                  else:
                      raise IntegrityError(args[0].decode())
              elif error == 'AtticRepository':
                  if old_server:
                      raise Repository.AtticRepository('(not available)')
                  else:
                      raise Repository.AtticRepository(args[0].decode())
              elif error == 'PathNotAllowed':
                  if old_server:
                      raise PathNotAllowed('(unknown)')
                  else:
                      raise PathNotAllowed(args[0].decode())
              elif error == 'ParentPathDoesNotExist':
                  raise Repository.ParentPathDoesNotExist(args[0].decode())
              elif error == 'ObjectNotFound':
                  if old_server:
                      raise Repository.ObjectNotFound('(not available)', self.location.orig)
                  else:
                      raise Repository.ObjectNotFound(args[0].decode(), self.location.orig)
              elif error == 'InvalidRPCMethod':
                  if old_server:
                      raise InvalidRPCMethod('(not available)')
                  else:
                      raise InvalidRPCMethod(args[0].decode())
              else:
                  raise self.RPCError(unpacked)
  
          calls = list(calls)
          waiting_for = []
          while wait or calls:
              if self.shutdown_time and time.monotonic() > self.shutdown_time:
                  # we are shutting this RemoteRepository down already, make sure we do not waste
                  # a lot of time in case a lot of async stuff is coming in or remote is gone or slow.
                  logger.debug('shutdown_time reached, shutting down with %d waiting_for and %d async_responses.',
                               len(waiting_for), len(self.async_responses))
                  return
              while waiting_for:
                  try:
                      unpacked = self.responses.pop(waiting_for[0])
                      waiting_for.pop(0)
                      if b'exception_class' in unpacked:
                          handle_error(unpacked)
                      else:
                          yield unpacked[RESULT]
                          if not waiting_for and not calls:
                              return
                  except KeyError:
                      break
              if cmd == 'async_responses':
                  while True:
                      try:
                          msgid, unpacked = self.async_responses.popitem()
                      except KeyError:
                          # there is nothing left what we already have received
                          if async_wait and self.ignore_responses:
                              # but do not return if we shall wait and there is something left to wait for:
                              break
                          else:
                              return
                      else:
                          if b'exception_class' in unpacked:
                              handle_error(unpacked)
                          else:
                              yield unpacked[RESULT]
              if self.to_send or ((calls or self.preload_ids) and len(waiting_for) < MAX_INFLIGHT):
                  w_fds = [self.stdin_fd]
              else:
                  w_fds = []
              r, w, x = select.select(self.r_fds, w_fds, self.x_fds, 1)
              if x:
                  raise Exception('FD exception occurred')
              for fd in r:
                  if fd is self.stdout_fd:
                      data = os.read(fd, BUFSIZE)
                      if not data:
                          raise ConnectionClosed()
                      self.rx_bytes += len(data)
                      self.unpacker.feed(data)
                      for unpacked in self.unpacker:
                          if isinstance(unpacked, dict):
                              msgid = unpacked[MSGID]
                          elif isinstance(unpacked, tuple) and len(unpacked) == 4:
                              # The first field 'type' was always 1 and has always been ignored
                              _, msgid, error, res = unpacked
                              if error:
                                  # ignore res, because it is only a fixed string anyway.
                                  unpacked = {MSGID: msgid, b'exception_class': error}
                              else:
                                  unpacked = {MSGID: msgid, RESULT: res}
                          else:
                              raise UnexpectedRPCDataFormatFromServer(data)
                          if msgid in self.ignore_responses:
                              self.ignore_responses.remove(msgid)
                              # async methods never return values, but may raise exceptions.
                              if b'exception_class' in unpacked:
                                  self.async_responses[msgid] = unpacked
                              else:
                                  # we currently do not have async result values except "None",
                                  # so we do not add them into async_responses.
                                  if unpacked[RESULT] is not None:
                                      self.async_responses[msgid] = unpacked
                          else:
                              self.responses[msgid] = unpacked
                  elif fd is self.stderr_fd:
                      data = os.read(fd, 32768)
                      if not data:
                          raise ConnectionClosed()
                      self.rx_bytes += len(data)
                      # deal with incomplete lines (may appear due to block buffering)
                      if self.stderr_received:
                          data = self.stderr_received + data
                          self.stderr_received = b''
                      lines = data.splitlines(keepends=True)
                      if lines and not lines[-1].endswith((b'\r', b'\n')):
                          self.stderr_received = lines.pop()
                      # now we have complete lines in <lines> and any partial line in self.stderr_received.
                      for line in lines:
                          handle_remote_line(line.decode())  # decode late, avoid partial utf-8 sequences
              if w:
                  while not self.to_send and (calls or self.preload_ids) and len(waiting_for) < MAX_INFLIGHT:
                      if calls:
                          if is_preloaded:
                              assert cmd == 'get', "is_preload is only supported for 'get'"
                              if calls[0]['id'] in self.chunkid_to_msgids:
                                  waiting_for.append(pop_preload_msgid(calls.pop(0)['id']))
                          else:
                              args = calls.pop(0)
                              if cmd == 'get' and args['id'] in self.chunkid_to_msgids:
                                  waiting_for.append(pop_preload_msgid(args['id']))
                              else:
                                  self.msgid += 1
                                  waiting_for.append(self.msgid)
                                  if self.dictFormat:
                                      self.to_send = msgpack.packb({MSGID: self.msgid, MSG: cmd, ARGS: args})
                                  else:
                                      self.to_send = msgpack.packb((1, self.msgid, cmd, self.named_to_positional(cmd, args)))
                      if not self.to_send and self.preload_ids:
                          chunk_id = self.preload_ids.pop(0)
                          args = {'id': chunk_id}
                          self.msgid += 1
                          self.chunkid_to_msgids.setdefault(chunk_id, []).append(self.msgid)
                          if self.dictFormat:
                              self.to_send = msgpack.packb({MSGID: self.msgid, MSG: 'get', ARGS: args})
                          else:
                              self.to_send = msgpack.packb((1, self.msgid, 'get', self.named_to_positional(cmd, args)))
  
                  if self.to_send:
                      try:
                          written = self.ratelimit.write(self.stdin_fd, self.to_send)
                          self.tx_bytes += written
                          self.to_send = self.to_send[written:]
                      except OSError as e:
                          # io.write might raise EAGAIN even though select indicates
                          # that the fd should be writable
                          if e.errno != errno.EAGAIN:
                              raise
          self.ignore_responses |= set(waiting_for)  # we lose order here
  
      @api(since=parse_version('1.0.0'),
           append_only={'since': parse_version('1.0.7'), 'previously': False},
           make_parent_dirs={'since': parse_version('1.1.9'), 'previously': False})
      def open(self, path, create=False, lock_wait=None, lock=True, exclusive=False, append_only=False,
               make_parent_dirs=False):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'),
           max_duration={'since': parse_version('1.2.0a4'), 'previously': 0})
      def check(self, repair=False, save_space=False, max_duration=0):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'),
           compact={'since': parse_version('1.2.0a0'), 'previously': True, 'dontcare': True},
           cleanup_commits={'since': parse_version('1.2.0a0'), 'previously': False, 'dontcare': True})
      def commit(self, save_space=False, compact=True, cleanup_commits=False):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def rollback(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def destroy(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def __len__(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def list(self, limit=None, marker=None):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.1.0b3'))
      def scan(self, limit=None, marker=None):
          """actual remoting is done via self.call in the @api decorator"""
  
      def get(self, id):
          for resp in self.get_many([id]):
              return resp
  
      def get_many(self, ids, is_preloaded=False):
          for resp in self.call_many('get', [{'id': id} for id in ids], is_preloaded=is_preloaded):
              yield resp
  
      @api(since=parse_version('1.0.0'))
      def put(self, id, data, wait=True):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def delete(self, id, wait=True):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def save_key(self, keydata):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def load_key(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def get_free_nonce(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def commit_nonce_reservation(self, next_unreserved, start_nonce):
          """actual remoting is done via self.call in the @api decorator"""
  
      @api(since=parse_version('1.0.0'))
      def break_lock(self):
          """actual remoting is done via self.call in the @api decorator"""
  
      def close(self):
          if self.p:
              self.p.stdin.close()
              self.p.stdout.close()
              self.p.wait()
              self.p = None
  
      def async_response(self, wait=True):
          for resp in self.call_many('async_responses', calls=[], wait=True, async_wait=wait):
              return resp
  
      def preload(self, ids):
          self.preload_ids += ids
  
  
  def handle_remote_line(line):
      """
      Handle a remote log line.
  
      This function is remarkably complex because it handles multiple wire formats.
      """
      assert line.endswith(('\r', '\n'))
      if line.startswith('{'):
          # This format is used by Borg since 1.1.0b6 for new-protocol clients.
          # It is the same format that is exposed by --log-json.
          msg = json.loads(line)
  
          if msg['type'] not in ('progress_message', 'progress_percent', 'log_message'):
              logger.warning('Dropped remote log message with unknown type %r: %s', msg['type'], line)
              return
  
          if msg['type'] == 'log_message':
              # Re-emit log messages on the same level as the remote to get correct log suppression and verbosity.
              level = getattr(logging, msg['levelname'], logging.CRITICAL)
              assert isinstance(level, int)
              target_logger = logging.getLogger(msg['name'])
              msg['message'] = 'Remote: ' + msg['message']
              # In JSON mode, we manually check whether the log message should be propagated.
              if logging.getLogger('borg').json and level >= target_logger.getEffectiveLevel():
                  sys.stderr.write(json.dumps(msg) + '\n')
              else:
                  target_logger.log(level, '%s', msg['message'])
          elif msg['type'].startswith('progress_'):
              # Progress messages are a bit more complex.
              # First of all, we check whether progress output is enabled. This is signalled
              # through the effective level of the borg.output.progress logger
              # (also see ProgressIndicatorBase in borg.helpers).
              progress_logger = logging.getLogger('borg.output.progress')
              if progress_logger.getEffectiveLevel() == logging.INFO:
                  # When progress output is enabled, we check whether the client is in
                  # --log-json mode, as signalled by the "json" attribute on the "borg" logger.
                  if logging.getLogger('borg').json:
                      # In --log-json mode we re-emit the progress JSON line as sent by the server,
                      # with the message, if any, prefixed with "Remote: ".
                      if 'message' in msg:
                          msg['message'] = 'Remote: ' + msg['message']
                      sys.stderr.write(json.dumps(msg) + '\n')
                  elif 'message' in msg:
                      # In text log mode we write only the message to stderr and terminate with \r
                      # (carriage return, i.e. move the write cursor back to the beginning of the line)
                      # so that the next message, progress or not, overwrites it. This mirrors the behaviour
                      # of local progress displays.
                      sys.stderr.write('Remote: ' + msg['message'] + '\r')
      elif line.startswith('$LOG '):
          # This format is used by borg serve 0.xx, 1.0.x and 1.1.0b1..b5.
          # It prefixed log lines with $LOG as a marker, followed by the log level
          # and optionally a logger name, then "Remote:" as a separator followed by the original
          # message.
          _, level, msg = line.split(' ', 2)
          level = getattr(logging, level, logging.CRITICAL)  # str -> int
          if msg.startswith('Remote:'):
              # server format: '$LOG <level> Remote: <msg>'
              logging.log(level, msg.rstrip())
          else:
              # server format '$LOG <level> <logname> Remote: <msg>'
              logname, msg = msg.split(' ', 1)
              logging.getLogger(logname).log(level, msg.rstrip())
      else:
          # Plain 1.0.x and older format - re-emit to stderr (mirroring what the 1.0.x
          # client did) or as a generic log message.
          # We don't know what priority the line had.
          if logging.getLogger('borg').json:
              logging.getLogger('').warning('Remote: ' + line.strip())
          else:
              # In non-JSON mode we circumvent logging to preserve carriage returns (\r)
              # which are generated by remote progress displays.
              sys.stderr.write('Remote: ' + line)
  
  
  class RepositoryNoCache:
      """A not caching Repository wrapper, passes through to repository.
  
      Just to have same API (including the context manager) as RepositoryCache.
  
      *transform* is a callable taking two arguments, key and raw repository data.
      The return value is returned from get()/get_many(). By default, the raw
      repository data is returned.
      """
      def __init__(self, repository, transform=None):
          self.repository = repository
          self.transform = transform or (lambda key, data: data)
  
      def close(self):
          pass
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_val, exc_tb):
          self.close()
  
      def get(self, key):
          return next(self.get_many([key], cache=False))
  
      def get_many(self, keys, cache=True):
          for key, data in zip(keys, self.repository.get_many(keys)):
              yield self.transform(key, data)
  
      def log_instrumentation(self):
          pass
  
  
  class RepositoryCache(RepositoryNoCache):
      """
      A caching Repository wrapper.
  
      Caches Repository GET operations locally.
  
      *pack* and *unpack* complement *transform* of the base class.
      *pack* receives the output of *transform* and should return bytes,
      which are stored in the cache. *unpack* receives these bytes and
      should return the initial data (as returned by *transform*).
      """
  
      def __init__(self, repository, pack=None, unpack=None, transform=None):
          super().__init__(repository, transform)
          self.pack = pack or (lambda data: data)
          self.unpack = unpack or (lambda data: data)
          self.cache = set()
          self.basedir = tempfile.mkdtemp(prefix='borg-cache-')
          self.query_size_limit()
          self.size = 0
          # Instrumentation
          self.hits = 0
          self.misses = 0
          self.slow_misses = 0
          self.slow_lat = 0.0
          self.evictions = 0
          self.enospc = 0
  
      def query_size_limit(self):
          stat_fs = os.statvfs(self.basedir)
          available_space = stat_fs.f_bavail * stat_fs.f_frsize
          self.size_limit = int(min(available_space * 0.25, 2**31))
  
      def key_filename(self, key):
          return os.path.join(self.basedir, bin_to_hex(key))
  
      def backoff(self):
          self.query_size_limit()
          target_size = int(0.9 * self.size_limit)
          while self.size > target_size and self.cache:
              key = self.cache.pop()
              file = self.key_filename(key)
              self.size -= os.stat(file).st_size
              os.unlink(file)
              self.evictions += 1
  
      def add_entry(self, key, data, cache):
          transformed = self.transform(key, data)
          if not cache:
              return transformed
          packed = self.pack(transformed)
          file = self.key_filename(key)
          try:
              with open(file, 'wb') as fd:
                  fd.write(packed)
          except OSError as os_error:
              try:
                  truncate_and_unlink(file)
              except FileNotFoundError:
                  pass  # open() could have failed as well
              if os_error.errno == errno.ENOSPC:
                  self.enospc += 1
                  self.backoff()
              else:
                  raise
          else:
              self.size += len(packed)
              self.cache.add(key)
              if self.size > self.size_limit:
                  self.backoff()
          return transformed
  
      def log_instrumentation(self):
          logger.debug('RepositoryCache: current items %d, size %s / %s, %d hits, %d misses, %d slow misses (+%.1fs), '
                       '%d evictions, %d ENOSPC hit',
                       len(self.cache), format_file_size(self.size), format_file_size(self.size_limit),
                       self.hits, self.misses, self.slow_misses, self.slow_lat,
                       self.evictions, self.enospc)
  
      def close(self):
          self.log_instrumentation()
          self.cache.clear()
          shutil.rmtree(self.basedir)
  
      def get_many(self, keys, cache=True):
          unknown_keys = [key for key in keys if key not in self.cache]
          repository_iterator = zip(unknown_keys, self.repository.get_many(unknown_keys))
          for key in keys:
              if key in self.cache:
                  file = self.key_filename(key)
                  with open(file, 'rb') as fd:
                      self.hits += 1
                      yield self.unpack(fd.read())
              else:
                  for key_, data in repository_iterator:
                      if key_ == key:
                          transformed = self.add_entry(key, data, cache)
                          self.misses += 1
                          yield transformed
                          break
                  else:
                      # slow path: eviction during this get_many removed this key from the cache
                      t0 = time.perf_counter()
                      data = self.repository.get(key)
                      self.slow_lat += time.perf_counter() - t0
                      transformed = self.add_entry(key, data, cache)
                      self.slow_misses += 1
                      yield transformed
          # Consume any pending requests
          for _ in repository_iterator:
              pass
  
  
  def cache_if_remote(repository, *, decrypted_cache=False, pack=None, unpack=None, transform=None, force_cache=False):
      """
      Return a Repository(No)Cache for *repository*.
  
      If *decrypted_cache* is a key object, then get and get_many will return a tuple
      (csize, plaintext) instead of the actual data in the repository. The cache will
      store decrypted data, which increases CPU efficiency (by avoiding repeatedly decrypting
      and more importantly MAC and ID checking cached objects).
      Internally, objects are compressed with LZ4.
      """
      if decrypted_cache and (pack or unpack or transform):
          raise ValueError('decrypted_cache and pack/unpack/transform are incompatible')
      elif decrypted_cache:
          key = decrypted_cache
          # 32 bit csize, 64 bit (8 byte) xxh64
          cache_struct = struct.Struct('=I8s')
          compressor = LZ4()
  
          def pack(data):
              csize, decrypted = data
              compressed = compressor.compress(decrypted)
              return cache_struct.pack(csize, xxh64(compressed)) + compressed
  
          def unpack(data):
              data = memoryview(data)
              csize, checksum = cache_struct.unpack(data[:cache_struct.size])
              compressed = data[cache_struct.size:]
              if checksum != xxh64(compressed):
                  raise IntegrityError('detected corrupted data in metadata cache')
              return csize, compressor.decompress(compressed)
  
          def transform(id_, data):
              csize = len(data)
              decrypted = key.decrypt(id_, data)
              return csize, decrypted
  
      if isinstance(repository, RemoteRepository) or force_cache:
          return RepositoryCache(repository, pack, unpack, transform)
      else:
          return RepositoryNoCache(repository, transform)
  